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Modern Geomatics Technologies and Applications
As we know the temporal changes of the Earth’s gravity field can be observed on a global scale
with low–low satellite-to-satellite tracking (SST) missions. Therefore, for a better understanding of the
faults, earthquake mechanisms and physics of the interior of the earth should be studied. In order to do so,
we should improve our knowledge of the earth mechanism and its gravity field. Because of the limitations
of measuring instruments and impossibility of collecting data from the entire surface of the Earth, Our
knowledge of the Earth’s gravity field is incomplete. Besides, to benefit from more fruitful studies,
periodic, global and homogeneous data collection is a must. Therefore, we need satellites with better orbits
and lower heights.
For this purpose, three satellites by the names of CHAMP (CHAllenging Mini satellite Payload) in
2000, GRACE (Gravity Recovery and Climate Experiment) in 2002 and GOCE (Gravity recovery and
steady-state Ocean Circulation Explorer) in 2004 were lunched. All of the scenarios had low and nearly
polar orbit. They collect data continuously and in a three-dimensional format. All of these scenarios can
separate non-gravitational from gravitational signal parts. In the scenarios with pair satellite (like
GRACE), inter-satellite distance changes are tracked and in the scenarios with single satellite (like
GOCE), the gravity gradiometry is checked. Accordingly, the final gravity signal is achieved Rummel et
al. (2002).
Through development of space geodetic techniques such as the satellite gravity missions,
coseismic gravity changes can be detected from space. The coseismic gravity change caused by the 2004
Sumatra earthquake was detected by GRACE Sun and Okubo (2004) and Han et al. (2006). The gravity
changes caused by the earthquake were calculated and interpreted by using a very simple method based on
a half-space earth model Han et al. (2006).
During the past two decades, satellite gravity (CHAMP, GRACE and GOCE) missions increased
the accuracy, spatial resolution, and temporal resolution of the Earth’s gravity potential models Elsaka et
al. (2014). In the future, we may have access to improved data if better scenarios are launched in different
configuration of formations. In order to obtain optimum scenarios different studies were published during
the last decades and they are all included in Elsaka et al. (2014). All of them reveal a substantial increase
in accuracy and sensitivity.
After Sumatra-Andaman earthquake and analysis of GRACE data, it was found out that using
GRACE data to detect coseismic effects was possible [e.g., (Cambiotti and Sabadini, 2012, Chen et al.,
2007, Dai et al., 2014, Han et al., 2006, Han et al., 2013, Han et al., 2010, Han et al., 2011, Heki and
Matsuo, 2010, Matsuo and Heki, 2011, Wang et al., 2012a, Zhou et al., 2012). The modern geodetic
techniques will enable us to have a better detection of the coseismic deformations such as displacement,
gravity changes, etc. [e.g., (Chang and Chao, 2011, Hayes, 2011, Ito et al., 2011, Kobayashi et al., 2011,
Li and Shen, 2015, Sato et al., 2011, Shao et al., 2011, Sleep, 2012, Suito et al., 2011, Suzuki et al., 2012,
Han et al., 2006, Wang, 2012, Wang et al., 2012b)].
The goal of this contribution is to focus on gravity satellites that sense earthquake signals in the
best quality via alternative configuration scenarios applied in future gravimetric satellite missions. Full-
scale simulations of various mission scenarios covering GRACE, GRACE-FO, Cartwheel, pendulum and
Helix were performed. In this work, one more month was added to the simulated time span to analyse the
simulated earthquake signals.
This article is therefore interested in studying the sensitivity of satellite gravity scenarios to gravity
changes caused by the Maule fault as the case study. The study is tested on real and hypothetical strike
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